Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Investigation of the influence of gas density on two-phase flow for mineral oil and SF6 pressurized in a rock-flow cell
Submission Author:
Marco Germano Conte , PR
Co-Authors:
Marco Germano Conte, Bruna Patricia Naidek, Hedilberto Barros, Moisés Marcelino Neto, Rigoberto Morales
Presenter: Bruna Patricia Naidek
doi://10.26678/ABCM.COBEM2021.COB2021-0917
Abstract
Gas-liquid two-phase flow has been widely investigated in the last decades. Most of the studies in this field focus on fluids at ambient conditions or high ratios of liquid density over gas density, e.g., water and air, mineral oil and light gases (air, N2), etc. However, in some industrial applications like offshore oil and gas production in deepwater, where the pressure is considerably high, the fluid densities are similar to each other and even of the same order of magnitude. Reproduce conditions like that in lab scale can be very challenging and risky because of the pressures involved, so in order to mimic this scenario at lower pressures, heavy gases at low pressure, e.g., SF6, are used to substitute the light gases at high pressure. In this paper, we will show the influence of pressure on the stratified flow using SF6 and mineral oil to achieve small ratios of liquid density over gas density. Experiments were performed using a rocking-flow cell of 26 mm I.D. and 960 mm length that was pressurized up to 20 bar at ambient temperature, i.e., about 20ºC. The gas density ranged from 6 kg/m³ up to 176 kg/m³, resulting in density ratios of 141 to 5. Different rotational speeds for a liquid loading and an angular displacement amplitude were tested. Mixing rules were used to predict the influence of dissolved SF6 over liquid properties. Recorded images of the experiments for low liquid loading show that the gas-liquid interface transition from a smooth surface to a wavy one as pressure increases, which is analyzed using Kelvin-Helmholtz instability theory.
Keywords
Two-phase Flow, Stratified flow, Rocking-flow cell, influence of gas density, instabilities of gas-liquid interface
